(aws-ecr): missing ecr supports for ipv6

### Describe the feature

Since may 2025, aws supports ipv6 for ecr https://aws.amazon.com/about-aws/whats-new/2025/05/amazon-ecr-support-ipv6/.

To use it we need to use `.dkr-ecr..on.aws` as image url.
But currently it seems that cdk only generates `.dkr.ecr..amazonaws.com` urls.

### Use Case

We have servers that don't have ipv4.
Currently, we need to use a vpc endpoint to reach ecr servers.

### Proposed Solution

Add a parameter in DockerImageAsset to chose which ecr repository will be used.
Or directly in fargate / server configuration.

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### AWS CDK Library version (aws-cdk-lib)

all

### AWS CDK CLI version

all

### Environment details (OS name and version, etc.)

all

Start by tracing the DockerImageAsset and Fargate/server configuration entry points that generate ECR image URLs, then compare the current URL form with AWS's IPv6 ECR form. Done means a supported configuration can select or generate the IPv6-compatible ECR repository URL for servers without IPv4.

Written by the indexing model from the issue text.